The correct option is C Shudra
Upanayana is a symbolic ceremony that marked an individual's entrance to the Hinduism. In medieval texts it is seen that the Upanayana ceremony was restricted to the 'Trivarnikas' only. 'Trivarnikas' included the upper castes of Brahmins, Kshatriayas and Vaisyas. Sudras, the lower caste people, were not allowed to undergo this Upanayana ceremony.